This invention relates to an article of manufacture for delivering drug or other active agent to the body through the skin for the production of a beneficial or therapeutic effect. In the past, various devices have been proposed for accomplishing such purposes and these range from adhesive bandages containing topical and systemically acting agents such as are disclosed in U.S. Pat. No. 3,249,109 Maeth, et al., U.S. Pat. No. 3,339,546 Chen or U.S. Pat. No. 3,598,122 Zaffaroni. In lieu of using an adhesive to maintain such a bandage in contact with the skin, it has been suggested that a source of a drug be maintained in contact with the skin by means of a rubber band such as is disclosed in U.S. Pat. No. 4,289,749 Keith, et al. It has also been proposed that a medicament impregnated fabric in the form of a cuff or sock be maintained in contact with the skin by means of resilient rubber threads woven into the fabric such as disclosed in U.S. Pat. No. 3,200,037 Curtay. Other approaches to delivering drugs to the external surface of the body include the concept of forming a glove from a film-like material which contains a medicament such as disclosed in U.S. Pat. No. 2,693,438 Ward and U.S. Pat. No. 3,328,259 Anderson. While all of the above concepts have the capability of delivering the active agent to the skin, problems exist either with respect to cost, complexity or capability of consistent performance. Thus, adhesive bandages require a separate adhesive material interposed between the active agent source and the skin, which adhesive must combine the necessary chemical and physical compatability with the active agent with appropriate adhesive characteristics. Woven fabrics require the formation of a fabric of dissimilar materials and the subsequent impregnation of the fabric with a suitable active agent. The use of a rubber band to hold an active agent reservoir in place requires at least two elements and may be susceptible to separation or displacement of the rubber band from the reservoir. With respect to medicated films in the form of gloves, cuffs or sleeves, they are typically formed in situ or are intended primarily for covering burnt or wounded skin and are dependent upon the adhesive characteristics of the film, their water solubility or the presence of a thermoplastic material softenable at room temperature to maintain the required contact between the glove and the body.
While it is known that rubber matrices having a drug dispersed within or confined inside their structure are useable as implantable drug reservoirs, such as is shown in U.S. Pat. No. 3,279,996 to Long for example, it has not heretofore been proposed or suggested that the elastic properties of elastomeric active agent containing structures be utilized as the means for maintaining the active agent releasing surface of the elastomeric device in close and intimate contact with the skin as a transdermal therapeutic system.
According to this invention, an elastomeric structure adapted to encircle or enclose a body member is provided which elastomeric structure has dispersed therethrough a quantity of active agent adapted to be dispensed to the skin and which elastomeric structure is maintained in contact with the skin primarily as a result of the elastic action of the structure itself. The therapeutic system of this invention is extremely simple to fabricate, can be made in many forms including bands adapted to encircle a body member such as a finger, leg or arm; cuffs adapted to encircle a joint such as an elbow, knee or shoulder; or gloves or socks adapted to completely enclose a hand or a foot, or as an elastic link in a belt, bracelet or band for example. By fabricating the elastomeric structure, such that in its relaxed condition, it is smaller than in its condition of use, the elastic force obviates the need for any adhesive to provide a firm contact between the therapeutic system and the skin thereby substantially simplifying the design and construction of the device as well as its subsequent removal and reuse. Further, by choosing rubbers exhibiting low stress relaxation properties a reusable device can be provided and rubbers exhibiting relatively constant stressstrain characteristics will be usable to produce a device which is adaptable to relatively wide range of body-member sizes without being too loose on small diameters or too tight on larger diameters.
It is accordingly an object of this invention to provide an elastomeric transdermal therapeutic system in which the elastic properties of the device itself provide the means for maintaining the device in contact with the skin.
It is another object of this invention to provide an elastomeric transdermal therapeutic system having a size, in its relaxed condition, which is smaller than its size in its condition of use.
It is another object of this invention to provide a monolithic, elastomeric transdermal therapeutic system.
It is another object of this invention to provide an elastomeric transdermal therapeutic system which may be applied and removed repeatedly.
It is another object of this invention to provide an elastomeric transdermal therapeutic system usable on a range of body member sizes.